I don't think they really are taking that much of a risk.
As the only person on this board who owned a Corvette (and was under 50) the old guys are still going to like it. The name/brand is enough for that, and no one who isn't a designer is going to say "I was going to buy one but now that it has trapezoidal tail lights, I'm going to get an M3 instead".
The Corvette has always been the American poster child for mullets, but the reality is there is no true "Sports car" in that price range from any other manufacturer. If you want a high powered, RWD vehicle you're either left going with one of the Pony cars (Camaro, Challenger, Mustang) or you have to start jumping way up the price ladder to the more prestigious vehicles that are way higher in price.
The Vette has always been an economical (high torque, low gearing, good gas mileage) practical (you can fit a bike in the back with the hatchback design) and fantastic handling sports car/GT car. Almost all of my car buddies out of school at one point or another went to a Corvette. My brother had one, uncle had one, it's just a great vehicle even with all the cheap rattles and junk that was associated with it.
Not only that, the Vette is the only car I have ever owned where owning one made you automatically feel like part of a community. I could never drive past another Vette driver without getting or giving a wave back. Little kids would stop me on the street and yell for a burnout. When I drive past another BMW driver at best they give me a dirty look...if they take enough time to look up from their cell phone.
GM did a lot of concepts for the Corvettes that were mentioned, like the early stingray concepts from the late 80's/early 90's that transformed it into everything from a Mid-Rear concept to a 2 seat roadster - and I think while any of those would have been "new and fresh" they would have diluted what makes it such a great car in the first place.
America. F yeah.